U.S. patent number 4,441,489 [Application Number 06/355,623] was granted by the patent office on 1984-04-10 for orthopaedic splints.
This patent grant is currently assigned to National Research Development Corporation. Invention is credited to David M. Evans, Barry O. Weightman.
United States Patent |
4,441,489 |
Evans , et al. |
April 10, 1984 |
Orthopaedic splints
Abstract
An orthopaedic splint is provided for treatment of injury to the
extensor tendon distal to the DIP joint in the finger, the splint
serving to hold the DIP joint in hyperextension and the PIP joint
in flexion, while allowing restrained extension of the PIP joint.
The splint suitably involves first and second portions each
including at least one plate curved to seat transversely over or
under a finger, the first portion also being longitudinally
inclined and provided with strapping to hold the DIP joint in
hyperextension, and the portions being resiliently and hingedly
interconnected to hold the PIP joint as required. This
interconnection conveniently involves like springs on respectively
opposite sides of the PIP joint, the springs preferably being of
mutually parallel flat spiral form.
Inventors: |
Evans; David M. (Farnham
Common, GB2), Weightman; Barry O. (Thames Ditton,
GB2) |
Assignee: |
National Research Development
Corporation (London, GB2)
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Family
ID: |
10520288 |
Appl.
No.: |
06/355,623 |
Filed: |
March 8, 1982 |
Foreign Application Priority Data
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Mar 10, 1981 [GB] |
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8107537 |
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Current U.S.
Class: |
602/22 |
Current CPC
Class: |
A61F
5/10 (20130101); A61F 5/05875 (20130101) |
Current International
Class: |
A61F
5/058 (20060101); A61F 5/01 (20060101); A61F
5/04 (20060101); A61F 5/10 (20060101); A61F
005/10 () |
Field of
Search: |
;128/77,87A,87R
;272/67,68,140 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1529910 |
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Jun 1968 |
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FR |
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929317 |
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Jun 1963 |
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GB |
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Other References
Barron & Saad, "Management of Extensor Tendon Injuries" from
The Hand: Operative Plastic and Reconstruction Surgery, published
1980..
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Primary Examiner: Yasko; John D.
Attorney, Agent or Firm: Cushman, Darby & Cushman
Claims
We claim:
1. An orthopaedic splint for the finger comprising a first portion
and a second portion respectively for location distally and
proximally of the proximal interphalangeal joint; said first
portion including two plates each curved to seat in one of palmar
and dorsal dispositions round a phalanx, said plates each having a
respective strap to hold the same releasably so seated, and said
plates being interconnected in mutually inclined manner for
respective location distally and proximally of the distal
interphalangeal joint to hold this joint in hyperextension; and
said first and second portions being resiliently and hingedly
interconnected to hold the proximal interphalangeal joint in
flexion while allowing restrained extension against the spring
force of this last interconnection.
2. An orthopaedic splint for the finger comprising a first portion
and a second portion respectively for location distally and
proximally of the proximal interphalangeal joint; said first
portion including a single plate curved to seat in one of palmar
and dorsal dispositions round a phalanx, said plate being elongated
transversely of its curve, having a longitudinal inclination
between its ends, and having individual straps at its ends for
respective location distally and proximally of the distal
interphalangeal joint to hold the same releasably in
hyperextension; and said first and second portions being
resiliently and hingedly connected to hold the proximal
interphalangeal joint in flexion while allowing restrained
extension against the spring force of such interconnection.
3. An orthopaedic splint for a finger comprising a first portion
and a second portion respectively for location distally and
proximally of the proximal interphalangeal joint, each said portion
including at least one plate curved to seat in one of palmar and
dorsal dispositions round a phalanx, at least said first portion
plate having strapping to hold the same releasably so seated, and
said first portion plating turning through an angle of about
20.degree. longitudinally of said phalanx to hold the distal
interphalangeal joint in hyperextension.
4. An orthopaedic splint for a finger comprising a first portion
and a second portion respectively for location distally and
proximally of the proximal interphalangeal joint, said first
portion holding the distal interphalangeal joint in hyperextension,
said first and second portions being resiliently and hingedly
interconnected by a common spring structure to hold the proximal
interphalangeal joint in flexion while allowing restrained
extension against the spring force of said structure, and said
structure holding said portions at a generally mutually
perpendicular inclination when unstressed.
5. A splint according to claim 4 wherein said spring structure
includes two like springs for location on respectively opposite
sides of the PIP joint.
6. A joint according to claim 5 wherein said two springs are of
mutually parallel flat spiral forms.
7. A joint according to claim 6 wherein said springs are spirally
wound to close with extension of the PIP joint.
8. A method of treating injury to the extensor tendon distal to the
proximal interphalangeal joint in the finger, which method
comprises splinting the finger to hold the distal interphalangeal
joint in hyperextension and the proximal interphalangeal joint in
flexion at approximately 90.degree., while allowing restraint
extension of the proximal interphalangeal joint.
9. A method according to claim 8 wherein the PIP joint extension is
resiliently restrained.
Description
This invention concerns orthopaedic splints and more particularly
such splints for use in connection with the distal interphalangeal
joint, hereinafter referred to as the DIP joint.
The invention has in fact been developed primarily for use in
treatment of the so-called mallet deformity. This deformity is
discussed in the book "The Hand: Operative Plastic and
Reconstructive Surgery", edited by Barron and Saad, and published
by Churchill Livingston, 1980. This book indicates that a mallet
deformity is the result of injury, open or closed, to the extensor
tendon distal to the proximal interphalangeal joint, hereinafter
referred to as the PIP joint. Conventional treatment for mallet
deformity is said to comprise splinting of the DIP joint in slight
hyperextension. This splinting is appropriate in the case of a
closed deformity, possibly after an initial period involving a cast
extending to the forearm, or following surgery in the case of an
open deformity.
Difficulty can arise with the splinting just described because the
PIP joint is left free to move. The ruptured tendon ends are
maintained in close proximity only if there is restricted extension
of the PIP joint which otherwise tenses the lateral bands with
flexion and separates the divided terminal extensor. However lack
of movement at the PIP joint during the relevant period of about
six weeks is itself problematical in tending to produce tendon
contracture.
An object of the present invention is to improve this situation and
this is effected by the provision of a splint which holds the DIP
joint in slight hyperextension and the PIP in flexion, while
allowing restrained extension of the PIP joint.
The benefit of this different situation is that the additional
splinting of the PIP joint in flexion relaxes the extensor tendon
distally so that small movements of this joint can be made without
separation of the tendon ends, and these movements allow
exercise.
The proposed splint suitably comprises a first portion and a second
portion respectively for location proximally and distally of the
PIP joint, said first portion holding the DIP joint in
hyperextension, and said first and second portions being
resiliently and hingedly interconnected to hold the PIP joint in
flexion while allowing restrained extension against the spring
force of such interconnection.
Normally each of said first and second portions will include at
least one plate curved to seat in palmar or dorsal disposition over
a phalanx, with at least said first portion having strapping to
hold the same so seated.
Conveniently a common spring structure is provided to afford both
the resilience and hingeing capability of the interconnection
between the first and second portions. Also, such structure
conveniently comprises like spring formations locatable in
respectively opposed dispositions laterally of the PIP joint,
suitable springs being of flat spirally wound formations in
mutually parallel dispositions.
A fuller understanding of the invention will be gained from the
following description of three forms thereof, given by way of
example, with reference to the accompanying drawings, in which:
FIG. 1 schematically illustrates in perspective view one form of
splint according to the invention,
FIG. 2 similarly illustrates the splint of FIG. 1 applied to a
finger,
FIG. 3 illustrates in application to a finger another form of
splint according to the invention by modification of the splint of
FIG. 1, and
FIG. 4 illustrates yet another such modified form of splint.
The splint of FIG. 1 is denoted generally at 10 and comprises two
like elongate members 11 formed to a particular shape as described
below, three similar curved plates 12 interconnecting the members
11, and three straps 13 respectively connected with the plates
12.
The shape of each member 11 involves a first end portion 14 which
continues at one end into a flattened spiral portion 15, and then
into a remainder consisting of a further intermediate portion 16
and a second end portion 17. These portions are all generally
coplanar, the portions 16 and 17 extend generally perpendicularly
to portion 14, and the portion 17 is inclined slightly relative to
portion 16 in an outward sense relative to the included angle
between these two portions and portion 14.
The plates 12 are of longitudinally curved, rectangular form and
their opposed end edges are respectively connected with the
corresponding portions 14 16 and 17 of the two members 11 to
interconnect these members in a mutually transversely-spaced
parallel disposition.
Each strap 13 is connected to a respective one of the plates to
extend from one end thereof and is releasably connectable with the
other end portion of its plate.
In an initial embodiment of this splint subjected to a clinical
trial the members 11 were of metal wire such that the spiral
portions 15 served as springs while the remaining portions were
relatively stiff, the plates were of sheet metal to be stiff but
had their concave surfaces covered with a cushioning layer of
foamed plastics material 18, and the straps 13 were of textile
fabric of releasably self-adhesive form.
FIG. 2 shows the usage of this splint in application to a finger 20
with the three plates respectively located dorsally over and
strapped to the three phalanges, with the members 11 located along
opposite sides of the finger, with the spiral portions 15 located
adjacent the PIP joint 21, and with the junctions of the portions
16 and 17 located in the region of the DIP joint 22. It will be
seen that this overall location is such that the DIP joint is held
in slight hyperextension by virtue of the inclination between
portions 16 and 17, and that the PIP joint is held in flexion by
virtue of the general perpendicularity between these last portions
and portions 14. Also, it will be appreciated that the PIP joint is
open to limited restrained extension movement by rotation of, and
against the inherent spring action of, the spiral portions 15 which
bias the splint, and the finger therewith, to the configuration
described above.
The splint of FIG. 1 is, of course, but one example of a
practicable form of the invention and various other such forms are
possible. Indeed another form is at present preferred following
continued development and trial.
FIG. 3 shows this preferred form which is modified relative to that
of FIG. 1 by integration of the two plates bordering the DIP joint
into a one-piece plate 23. This plate 23 is generally rectangular
but transversely curved to form a channel extending along and over
the two distal phalanges, and having slight longitudinal angling,
suitably of about 20.degree., part way therealong to locate the DIP
joint in slight hyperextension.
Another modification is seen in that the spiral portion springs are
preferably wound to close during extension of the PIP joint rather
than open. This change better preserves the spring action for a
given wire material.
Also, it is found unnecessary in practice to provide a strap for
the proximal plate 12 because the spring force will suitably locate
this plate.
It will also be noted that the plates 12 and 23 are rounded at
their mutually remote ends.
The angle between the portions 14 and 16 is preferably a little
less than 90.degree. when the splint is in an unstressed state, off
the finger, this angle suitably being 80.degree. to 85.degree..
The overall proportions and dimensions of the splint are preferably
such that, in use, the distal and proximal straps 13 are
respectively located close to the end of the finger and the PIP
joint, and the plate 12 is located towards the proximal end of the
associated phalanx and may be slightly longitudinally upwardly
inclined to seat against the adjacent knuckle. At the same time,
the spiral springs preferably have their centres located in the
region of the PIP joint axis.
The preferred locations just discussed can be reasonably well
attained by the provision of a very modest range of sizes of splint
to suit different fingers.
FIG. 4 shows another modification relative to FIG. 1 in which the
middle plate, differentiated by reference numeral 24, is disposed
to adopt a palmar location relative to the finger.
Clearly yet other variations are possible. For example, the
proximal plate could also adopt a palmar location, but it is
preferred that such a location be avoided for the distal plate so
that the tactile facility is retained. The members 11 can be
integrated by formation from one piece of material, with this piece
extending across the proximal and/or distal plate to reinforce the
same. The splint need not involve hingeing and spring action from a
common structure, although this can clearly be simple and
convenient in manufacture. Lastly, the supportive hinge and spring
functions of the plates and members may, within the limit in terms
of simplicity of structure, be served by a one-piece moulding of
plastics material.
* * * * *